Carrying ram, gate, and hydraulic control



Nov. 24, 1964 o. c. MENSINGER ETAL CARRYING RAM, GATE, AND HYDRAULICCONTROL 5 Sheets-Sheet 1 Original Filed June 16, 1958 INVENTORS. C.MENSINGER W. SPENCER OVIE ROGER Nov. 24, 1964 o. c. MENSlNGER ETAL3,158,274

CARRYING RAM, GATE, AND HYDRAULIC CONTROL Original Filed June 16, 1958 5Sheets-Sheet 2 ATTY.

Nov. 24, 1964 o. c. MENSINGER ETAL 3,153,274

CARRYING RAM, GATE, AND HYDRAULIC CONTROL Original Filed June 16, 1958 5Sheets-Sheet 3 INVENTORS. OVIE C. MENSINGER ROGER W. SPENCER ATTY.

Nov. 24, 1964 o. c. MENSINGER ETAL 3,158,274

CARRYING RAM, GATE, AND HYDRAULIC CONTROL Original Filed June 16, 1958 5Sheets-Sheet 4 FIG. 7

.INVENTORS MENSINGER BY ROGER W. SPENCER OVIE ATTY.

Nov. 24, 1964 o. c. MENSINGER ETAL 3,158,274

CARRYING RAM, GATE, AND HYDRAULIC CONTROL Griginal Filed June 16, 1958 5Sheets-Sheet 5 INVENTORS. MENSINGER OVIE C ROGER W. SPENCER a 8 Y BATTY.

United States Patent O "we 3,158,274 CARRYING RAM, GATE, ANDHYlEl-RAULHQ NTRL This invention relates to load handling devices forstraddle carriers or gantry trucks as they are sometimes called, andparticularly to a load handling device which will facilitate thehandling of coils of metal in strip form,

coils of wire and the like.

This application is a continuation of application Serial No. 742,164,filed June 16, 1958, now abandoned.

Straddle carriers have been in use for a considerable period in thelumber industry, the metal industry and elsewhere. The conventionalarrangement for handling material with such machines is to load thematerial to be transported on a bolster. Such a bolster may consist of arectangular frame or platform of wood or steel, which is arranged tosupport the material to be carried above it, and to be picked up bybeing engaged by the load hooks of the straddle carrier beneath andalong the two longer sides of the rectangular frame.

Straddle carriers are provided with depending load hooks along the twosides of the machine just inside the wheels. These hooks are arrangedfor small lateral movement so that they may be moved apart to provideclearance as the carrier is driven over the bolster. After the carrieris in position over the bolster the hooks are moved inwardly beneath thebolster. Then the hooks may be raised vertically a sufiicient amount toraise the bolster with its load off of the ground and allow the bolsterand the load to be transported to another location where they are setdown again.

Heretofore, coils of metal strip and wire have generally been handled onbolsters in the same manner as other materials. The handling of suchcoils with a straddle carrier in this manner is generally much moreconvenient and less costly than other methods of handling coils,however, if conventional bolsters are used it is necessary to load thecoils onto the bolster before the straddle carrier can pick them up.Similarly, it is necessary to unload them from the bolster again at theend of the trip by the straddle carrier.

US. Patent No. 2,975,922, dated March 21, 1961, and issued in the nameof Raymond A. Dodge, discloses a load handling device which includes apair of stringer members located in parallel spaced apart relation whichare adapted to be engaged by the load hooks of a straddle carrier. Bracemeans interconnect the stringer members at one end thereof, and a rammember is cantilevered from the brace means and extends centrally of andabove the stringer members.

In operation, this previous load handling device is carried by thestraddle carrier and the coils which the carrier is to pick up arearranged with the holes in the coils located coaxially so that the ramportion of the load handling device can enter the openings of all of thecoils ing the load hooks so that the ram disengages the coils and thenbacking up the straddle carrier from the coils.

3,158,234 Patented Nov. 24, 1964 The present invention constitutes animprovement upon the above-described apparatus. By reference to theabovementioned patent it may be seen that the ram member is supported atonly one end thereof which requires a sturdy structure to prevent damagethereto when loaded. Also, since the ram is open at the oneend whenloaded it would be possible under certain conditions of operation and inmaneuvering the straddle carrier over rough or downwardly inclinedsurfaces for one or more coils to become disengaged from the ram.

With the foregoing in mind, it is a primary object of the presentinvention to provide a coil handling device of the cantilever ram typewherein during load carrying operations improved means is provided forclosing and supporting the ram at the normally open end thereof.

Another object is to provide a ram type coil handling device selectivelysupportable at one end and elevatable in a relatively unloaded conditionregardless'of whether said one end is supported, and elevatable in arelatively loaded condition only when said one end is supported.

It is a further object to provide an elevatable coil handling device ofthe cantilever ram type having a pivoted gate member at one end thereofwhich may be unlocked from and pivoted outwardly of the ram for loadingand closed over and locked to the open ram end for supporting the sameduring load carrying operations, and improved gate control means forcontrolling sequentially the movement and the locking of the gatemember.

Still another object of the present invention is to provide in a loadhandling device of the elevatable ram type having ram support meansmovable into and out of engagement with the ram end means for lockingthe support means to the ram, improved control means for sequentiallyunlocking and disengaging the support means from the ram andsequentially engaging and locking the support means with the ram, plusinterlocking control means for permittin elevation of a predeterminedload on the device only when the support means engages and is locked tothe ram.

It is a further object of the present invention to provide in a coilhandling device improved control means for controlling remotely meansdisposed to support the open end of the device.

It is a further object of the present device to provide in acantilevered type load handling device having means selectivelysecurable to the open end thereof improved interlocking control means toprevent lifting of a load prior to securing the securable means to theopen end of the device.

Other objects and advantages of the present invention will becomereadily apparent from the following detailed description of oneillustrative embodiment thereof shown in the accompanying drawingswherein:

FEGURE 1 is a view in perspective of the improved coil handling devicein its operative carrying position upon a conventional straddle carrierwhich carrier is shown by dotted line representation;

FIGURE 2 is a view in perspective of the improved coil handlingattachment shown apart from its connection with a straddle carrier;

FIGURE 3 is a fragmentary side elevational view showing the forward endof the improved coil handling apparatus with the pivotal gate member inits fully closed position; 7

FIGURE 4 is a front elevational view of the improved coil handlingattachment; the view being taken substantially along the line 4-4 ofFIGURE 3;

FIGURE 5 is a fragmentary side elevational view similar to FIGURE 3showing the pivotal gate member in a partially open position;

FIGURE 6 is a front elevational view similar to FIG- o ea URE 4; theview being taken substantially along the line 66 of FIGURE FIGURE 7 is aschematic hydraulic diagram showing the relationship of the varioushydraulic components for actuating the improved coil handling apparatus;and

FIGURE 8 is a schematic wiring diagram for illustrating the relationshipand operation of the various electrical elements for the improved coilhandling apparatus.

Referring now to the drawings and particularly to FIGURE 1, there isillustrated by dotted line representation and indicated generally by thenumeral it), a straddle carrier or gantry truck of the type with whichthe present load handling device may be used advantageously. The carrier10 includes a pair of side frame portions 12 which are interconnected byan overhead top portion (not shown) to form the gantry structure. Themachine 10 includes a pair of front dirigible wheels 14 and a pair ofrear dirigible drive wheels 16 (only one of which appears in thedrawing). The machine is propelled by an internal combustion engine orother suitable prime mover which may be located in the compartment 18.The prime mover actuates the rear drive wheels 16 by means of a chaindrive mechanism or other equivalent drive means. The front and reardirigible wheels 14 and 16 are connected to and operated by a suitableoperators steering wheel which is located in the operators compartmentat the top of the vehicle.

The machine 10 includes a pair of lift or load hooks 17 which dependjust inside the wheels adjacent the sides of the vehicle. These loadhooks are arranged to be moved laterally in and out a small amount. Theyare also arranged to be raised and lowered in a manner well known in theart. The hooks may be operated hydraulically both for their lateralmovements and their vertical movements, or they may be operated bymechanical or other equivalent means if desired, all of which is wellknown in the art. The power for operating the hooks ordinarily isderived from the same prime mover which propels the vehicle 10.

The load handling device of the present invention is shown in positionon the straddle carrier in FTGURE l and removed from the carrier inFIGURE 2 and is designated generally by the numeral 29. The device 20includes a pair of longitudinally extending frame or stringer members 22which are arranged in parallel relation and are located so that they maybe supported from and above the load hooks 17. The stringer members 22are provided with downwardly projecting leg members 24 adjacent each endthereof which are engaged by the load hooks 17. Also, the leg members 24rest on the ground or other supporting surface and maintain the stringermembers 22 substantially above such surface so that the load hooks mayenter beneath the stringer members to enable the carrier to pick up theload handling device.

The load handling device 26 further includes a transverse brace member26 which is connected between the stringer members 22 adjacent one endof the load handling device. Secured to the brace member 26 on oppositesides thereof as illustrated, are a pair of depending substantiallytriangular plates 28 which form with the brace member a rigid invertedpyramidal structure. Adjacent the apex of the inverted pyramid alongitudinally extending ram member 30 is connected. The ram 36 ispreferably formed of a hollow steel tube which extends longitudinallyforwardly from the brace member 26 midway between the stringer members22 and in parallel relation with the stringer members. The ram 30 has atapered nose portion 32 at the foward end (see FIG- URES 3 and 5) tofacilitate the entry of the ram into coils of metal strip and wire andthe like.

At its forward end, the load handling device further includes atransverse brace member 34 secured to upturned extensions 36 of thestringer members 22. Suitable strengthening gusset plates 38 areprovided at the juncture at each end of the brace member 34 where itjoins with the respective stringer 22. Preferably, the brace members 26and 34, and the plates 28 and 38 are all welded solidly to theirrespective joining elements and to the stringer members 22 to form arigid unitary structure.

The load handling device 20 of the present invention includes apivotally hinged gate member generally indicated at 49. The gate memberd0 generally comprises a pair of diagonally extending frame members 42and 44 having ends which join together and terminate adjacent the noseportion 32 of the ram when the gate member is closed. The frame members42 and 44 are braced intermediate their ends by means of a transverselyextending brace member 43 and are secured together adjacent the nose ofthe ram by means of a gusset plate 45. The opposite ends of these framemembers 42 and 44 are each provided with a sleeve member 46 securedthereto conveniently by welding. The sleeve members 46 are keyed to, orotherwise secured to, shafts 48 extending therethrough. The shafts 48extend laterally outwardly from the sleeves 46 where they are journaledin bearing members 50 which are rigidly secured to the gusset plates 38.Approximately midway of their lengths each of the shafts 48 are providedwith sprockets 52 which are rigidly keyed thereto and are adapted to bedriven by a chain 54 which is in turn driven by a sprocket 56 secured toa shaft 58. The sprockets and chains are enclosed by suitable covermembers 57 for safety reasons and to keep foreign particles out of thedrive means. The shafts 58 are journaled adjacent their outboard endswithin suitable hearing members 6% which arerigidly secured to thetransverse brace member 324. Theshafts 58 at their inboard ends aresuitably coupled to the output shaft 62. of a reversible hydraulic motorgenerally indicated at @4- which, through the mechanism above described,is adapted to selectively move the gate member 40 into and out ofengagement with the nose portion 32 of the ram 30. The operation andcontrol of the hydraulic motor 64 will be more fully describedpresently.

At the joint between the gate frame members 42 and 44 adjacent the noseportion 32 of the ram 30, there is provided a collar 66 secured to thegusset plate 45. An aperture 68 extends through the collar 66 and thegusset plate 45 and is adapted to register with a stubshaft '74 rigidlysecured to the ram 3 and projecting outwardly therefrom. The aperture 68and the stub-shaft 7d are suitably formed as shown so as to have asubstantially close sliding fit with one another as the gate member 4%is pivotally moved into and out of engagement with the ram 38. To theend of positively locking the gate member 4%) to the ram 30, thestub-shaft 70 is provided on the upper portion thereof toward itsoutboard end with a cut out notch 72 (FIGURE 5). Pivotally connected tothe collar member 66 as at 74 is a triangular shaped locking plate '76.When the gate member 40 is in the closed or carrying position as shownin FIGURE 3, the locking plate 76 is adapted to be pivoted so as toregister with the notch '72 in the stubshaft 7% to thereby securelyconnect the gate member 44} to the ram 39. Pivotally connected to onecorner of the locking plate 76 is a yoke member 78 which in turn isattached to one end of the actuating shaft 80 of a double-actinghydraulic cylinder 82. At its opposite end, the cylinder 82 is pivotallyconnected to the frame member 42 by means of a yoke member 34 and asupporting bracket 86. Movement of'the actuating shaft 8t) under thecontrol of the cylinder 82 causes the locking plate 76 to be moved intothe locking and unlocking positions as shown in FIGURES 3 and S. Thecontrol of the cylinder 82 to accomplish such movement will be describedpresently.

Referring now to FIGURES 7 and 8, the control means for operating theimproved coil handling attachment 20 and the locking gate member 40 willnow be described.

FIGURE 7 illustrates diagrammatically a form of hydraulic circuit whichmay be employed in connection with the present invention. In thisdiagram, the prime mover of the straddle carrier 10 is designated by thereference numeral 88. Connected to be driven by the prime mover 88 are apair of positive displacement pumps 9t and 92 of suitable and Well knowntype. intake conduits 94 and 96 connect, respectively, the pumps 90 and92 with a suitable reservoir or sump 98 containing the hydraulic fluidfor the system.

Anoutlet conduit 19% connects the pump 91 to a suitable manuallyoperated control valve 1tl2 of well known type for selectivelycontrolling the operation of 'a pair of double-acting hydraulic motors11M and 1116 which are connected to the load hooks of the straddlecarrier 16 for raising and lowering same as desired and in a manner wellknown in the art and to which the coil handling attachment 21) isconnected for operation as above described.

An outlet conduit 10% connects the pump 2 to a suitably mmually operablecontrol valve 110 which is of the same general type as the control valve1%2 and is adapted to selectively connect the reversible rotaryhydraulic motor 64 and the double-acting cylinder 82 into the circuitfor pivoting the gate member 49 and locking same into position on theram 33 as above described. A suitable pressure relief valve 1139 of wellknown type is provided in the conduit 1% to relieve excessive pressures.

The control valve 111 as shown in the diagram, is in a neutral position.When in this position, oil flow from the pump 92 is by-p-assed throughthe valve 11% to the sump $8. Let it now be assumed that the gate member4'1) is in its full open position and that the ram 30 has been loadedwith a quantity of coils for transporting from one location to anotherin the manner described in the previously mentioned patent. inaccordance with the present invention it is now desired to have the gatemember 461 pivot to its closed position and be locked therein to the ram36.

The control valve 110 is provided with an operating lever 112 which maybe selectively moved from the neutral position to two diiierentoperating positions which shall be herein designated as gate open andgate close positions. When the operating lever is moved into the gateclose position the conduit 168 will be con nected through the valve 110to a conduit 114 which leads to a sequence and check valve of suitabletype and generally designated at 116. The valve 116 controls thesequence of oil flow from the conduit 114 through a pair of conduits 113and 120 by pressure rise within the valve. Valves of this type arewell-known in the art and a detailed description thereof is not believedto be necessary herein. An example of one type of valve suitable foroperation in the present circuit is one manufactured by VickersIncorporated under their model number RCT-03-D2. it should sufiice forthe present disclosure tomerely point out that the valve 115 isconstructed to operate such that oil flow entering the pressure inlet115 is directed into the conduit 118 to the rotary hydraulic motor 64 soas to cause a counterclockwise rotation thereof as viewed in thediagram, and is blocked from entering the conduit 121 until the pressureconducted through a passage 117 overcomes an adjustable valve spring 119to move a piston 125 therein. Full pressure is then available at asecondmy outlet to the conduit 120. Reverse free flow through the valveis provided by means of a spring loaded one-way check valve 127 thereinwhich connects the conduits 118 and 126 From the foregoing descriptionit should be apparent that when the valve 110 is actuated to the gateclose position, the rotary hydraulic motor 64 will be operated to rotatein the counterclockwise direction throughout its full range of movementprior to the admission of fluid under pressure into the conduit 120.Such movement of the motor M, will by means of the chain and sprocketconnection previously described, cause the gate member 6 40 to bepivoted to its closed position in engagement with the nose portion 32 ofthe ram 319.

When the motor 64 has completed its full range of movement as abovedescribed, the sequence valve 116 will then operate to cause fluid underpressure to be admitted into the left hand end of the double-actinghydrauiic cylinder 32 which will impart a movement to the actuatingshaft 8d to thereby cause the locking plate 76 to be moved intoengagement with the slot 72 in the stub-shaft 711 on the ram 30 aspreviously described. While the cylinder 52 is being actuated as abovedescribed, the right hand end thereof is connected to the reservoir orsump 9% by means of a conduit 122, a sequence valve generally indicatedat 124-, a conduit 126, suitable connections through the valve and adrain conduit 128. The outlet side of the motor 64 is also connectedtothe sump at this time by means to be described presently.

A suitable pilot check valve 121 is connected in parallel with theconduits 121i and '122'by means of a conduit 123 to prevent reverse flowthrough the cylinder 82 in the event of seepage through the rotaryhydraulic motor 64.

. The conduit 123 serves as a pilot line to release the check valve 121when reverse flow under pressure is desired, as will appear presently.

When the valve 11% is actuated to the gate open position by means of ashifting of the operating lever 112, the conduit 1118 will be connectedthrough the valve 111? to the conduit 126 and pressure fluid will bedirected through the sequence valve 124 (which is identical to the valve116) to the conduit 122 and into the right hand end of the double-actinghydraulic cylinder 82. The pressure fluid will also be directed throughthe conduit 123 to release check valve 121 as above mentioned. Thepressure fluid entering the cylinder 82 will result in a movement of theactuating shaft 8% so as to unlock the locking plate 76 as should now beapparent. When the cylinder 82 has completed the unlocking stroke, thesequence valve 124 will be actuated to cause the pressure fluid to flowthrough a conduit 131) into an adjustable counterbalance valve 132 andthrough a conduit 134 into the rotary hydraulic motor 64 causing it torotate in a clockwise direction. Such rotation of the motor will,through the chain .and sprocket connections previously described, resultin a movement of the gate member 40 into its fully open position.

As above mentioned, an adjustable counterbalance valve 132 is interposedbetween the conduits 131) and 134 leading from the sequence valve 124 tothe rotary hydraulic motor 64. This counterbalance Valve 132 is similarto the sequence valves and is also of a type well-known in the art and adetailed description thereof is not deemed necessary herein. It shouldsufiice herein to point out that the valve 132 is provided formaintaining a back pressure to counteract the hydraulically sustainedload of the gate member 4% to thereby prevent the weight of the gatemember from causing it to fall too rapidly during the closing operation.During the opening operation of the gate member as above described,pressure fluid flowing from the conduit 139 through the valve 132,conduit 134. and into motor 64, passes through a restriction or meteringorifice 135 in the valve 132. This restriction will result in a backpressure being created in the conduit between the valves 124 and 132.Such back pressure causes a one-way check valve 13% to be moved ofi itscheck valve 138 prevents direct communication between the conduits 134and 1311 via the by-pass connection and all of the fluid must thereforepass through the metering orifice 136 into the conduit 13%, thence intothe sequence valve 124, conduit LAB, valve 110 and drain conduit 128.The metering orifice thus creates a back pressure during the closingoperation to restrict the flow of fluid from the motor 64 to therebycounterbalance and compensate for the weight of the gate member 4b inorder to prevent the gate member from closing too rapidly during theclose operation. Thus, the closing movement of the gate member issubstantially limited to the speed at which the rotary hydraulic motor64 drives same through the chain and sprocket drive means.

Interlocking control means is also provided in connection with thepresent invention to prevent lifting of the loaded coil carryingattachment 21) by the load hooks of the straddle carrier if the gatemember 40 is not fully closed and locked into position against the ram30. To this end, it should be noted that a branch conduit 14% from theconduit 1011 leads to a main relief valve M2 connected in the circuit tothe load hook actuating hydraulic motor 1% and 1% previously described.This relief valve 142 serves the conventional function of relievingexcessive pressures in the circuit and for bypassing the pressure fluidto the sump 98 when the motors 1M and 106 are not operating or at suchtimes as the motors have been actuated and are at their fully extendedpositions. Attached to the vent connection of relief valve 142 by meansof a suitable conduit 1&3 is a solenoid operated valve 144. The solenoidoperated valve 144 is of the normally open type and is closed byenergization of a solenoid 1 26 under the control of a gate switch 185to be presently described. A remote or secondary relief valve 154 isconnected in series with the main relief valve and the solenoid valve144 by means of a suitable conduit 152.

The main relief valve 142 is normally set to relieve pressures in excessof, for example, 1450 pounds per square inch. The vent connection onthis relief valve 142 provides for the series connection with thesecondary relief valve 151) through the solenoid operated valve 144 toin effect reduce the operating pressure of the main relief valve 142 aswill appear presently. Since the solenoid operated valve 144 is normallyopen, the secondary relief valve 150 is normally operative.

Referring briefly to FIGURES 3 to 6 inclusive, it may be seen that thegate switch 185, above mentioned,

is of the normally open type and is closed when the gate member 4!) ismoved to its completely closed position as shown in FIGURES 3 and 4. Theswitch 185 generally consists of a housing 192 having a pair ofstationary electrical contacts shown at 194 secured thereto. A springloaded switch plunger 196 is mounted for reciprocating movement withinthe housing 192 and carries thereon a conductor 198 which is adapted tobridge the gap and complete an electrical connection through thecontacts 194. When the gate member 49 is not completely closed, theplunger 196 is biased to assume the position shown in FIGURE 6 whereinthe conductor 198 is out of engagement with the contacts 194, thus asabove mentioned it is a normally open switch.

Referring now back to FIGURE 7, if the gate member 46 is not fullyclosed, the gate switch 185 is open which results in de-energization ofthe solenoid 146 causing the valve 144 to remain open. This in turnresults in an opening of the hydraulic circuit to the secondary reliefvalve 150. The secondary relief valve is set to operate so as to relievepressures in excess of, for example, 250 pounds per square inch. Thislow pressure relief permits picking up the coil ram attachment withoutload. If, however, there were coils in position on the ram 30, and thegate member 49 were not fully closed, the coil ram attachment 21 couldnot be raised because of insufficient pressure. The aforementionedarrangement provides a safety feature which serves to prevent damage tothe ram 30.

Referring now to FIGURE 8 which illustrates diagrammatically anelectrical circuit suitable for operation of the mechanism of thepresent invention; it may be seen that electrical power to energize thecircuits shown is obtained from a battery 162 which may be in theignition system for the prime mover 88 of the straddle carrier it Thebattery 162 is conventionally grounded as at 164 and is connected at theother or hot side to a pressure switch 166 by means of a conductor 168.The pressure switch 166 is not an essential element'in the circuit, butis here shown inasmuch as it does serve dual useful purposes. The switchis of conventional type and need not be described fully herein. Anexample of a commercially available switch of this type is onemanufactured by John W. Hobbs Corporation, Division of tewart WarnerCompany, under their model MI-672. The pressure switch serves toeliminate additional and unnecessary current load on the ignition switchof an electrical system of this type and makes it possible to supplyelectricity to the accessory components only if the engine or primemover is running; This then provides an automatic disconnect when theprime mover 88 is stopped. A conventional fuse block 170 may also, butnot necessarily, be placed in the circuit in series with the pressureswitch 166.

Mounted within the operators compartment of the straddle carrier 10,preferably on the instrument panel, or otherwise, are a pair ofindicator lights 172 and 174. The indicator light 172 may, for example,be a green light and when lighted as hereinafter described will indicatea safe operating condition. The indicator light 174 may, for example, bea red light and when lighted as hereinafter described will indicate anunsafe operating condition. The indicator light 172 is herein used toindicate that the gate member 40 is closed and locked, and that,therefore the unit is safe for operation. Current for the light 172flows from the fuse block 170 through a conductor 176 to one terminal ofthe light socket. The other terminal of the light socket is connected bymeans of a conductor 178 to one terminal 180 of a three terminal plug-inconnector generally indicated by the numeral 182. The plug-in connectionof the connector 182 is normally made when the coil carrying attachment26 is to be used with a straddle carrier in accordance with the previousdescription. A conductor 184 leads from the terminal 180 to one side ofthe gate switch 185. The gate switch 185 is connected in series, bymeans of a conductor 186 to one side of a lock switch 188, the otherside of which is grounded to the frame as indicated at 190.

A second gate switch 148 is provided which is similar in construction tothe previously described gate switch 185 except that whereas the switch185 is normally open, the switch 148 is normally closed. That is, whenthe gate member 41 is in its open position, as shown in FIGURE 6 thegate switch 148 is closed. Referring briefly to FEGURE 4, it may be seenthat the switch generally consists of a housing 154 having a pair ofstationary contacts 156 secured thereto. A spring loaded switch plunger158 is mounted for reciprocating movement within the housing 154 andcarries thereon a conductor 16!) which is adapted to bridge the gap andcomplete an electrical connection through the contacts 156. When thegate member 4t) is not completely closed, the plunger 158 is biased toassume the position shown in FIGURE 6 wherein the conductor 166 is inengagement with the contacts 156, thus as above mentioned it is anormally closed switch.

As above mentioned, the gate switch 185 and the lock switch 188 areconnected in series in the circuit. The lock switch 188 is also of thenormally opened type.

' Referring to FIGURES 4 and 6, it may be seen that the lock switch 138is attached to the gate member 40 and is arranged so as to be actuatedby an abutment member 20!) which may be mounted upon or arranged to bemoved upon movement of the locking plate 76 so that when the lockingplate 76 is moved to its locking position as seen in FIGURE 4, theplunger of the switch is depressed so as to close the circuittherethrough.

As previously described, the gate member 40 is moved into its closedposition prior to the actuation of the locking plate 76. It thereforefollows that the switches 185 and 183 will likewise be sequentiallyoperated. It is important to note that because of the series connectionsof switches 185 and 188, both switches must be closed in order toestablish a'circuit through the safe indicator light 172.

The indicator light 174 receives current from the fuse block 170, in thesame manner as the indicator light 172, by means of a jumper conductor202 between the two lights. The other connection to the indicator light174 is through a conductor 204 to a terminal 206 of the plugin connector182. A conductor 298 leads from the terminal 206 to one side of the gateswitch 148 (previously described), the other side of which is suitablygrounded to the frame as indicated at 216.

The solenoid 146 which operates the solenoid valve 144 is connected inparallel with the safe indicator light 172 by means of a pair ofconductors 212 and 214.

As previously mentioned, the gate switch 185 is of the normally openedtype. When the gate member 40 is not fully closed, the switch 185 isopened, therefore, the green indicator light 172 will not be illuminatedand also the solenoid 146 will be de-energized. It should be noted alsothat the red indicator light 174 will be illuminated at all times,except when the gate member 49 is fully closed, and thereby wouldindicate an unsafe operating condition.

The plug-in connector 182 is provided with a third terminal 215. Leadingfrom the terminal 216 is a conductcr 218 which is suitably grounded asat 220 to the frame of the straddle carrier 10. Another conductor 222leads from the terminal 216 and is suitably grounded as at 224 to thecoil carrying attachment 20. The pur pose of these conductors 218 and222 is to make certain of a positive ground connection between theattachment and the carrier frame.

Having now described generally the structure of the elements making upthe present invention together with the hydraulic control means andelectrical circuitry for operating same; it is believed that theinvention may be clarified and summarized by describing a typicaloperation wherein a straddle carrier equipped with the improved coilhandling attachment picks up a load of coils of metal or wire,transports them, and deposits them at the destination, all without theassistance of a helper on the ground. The operator in the straddlecarrier performs all operations from within the cab merely by selectingand manipulating in the proper sequence a plurality of control elements.

Let it be assumed for the following example that the gate member 49 isin its full open position and that the coil handling attachment 21) iselevated by the load hooks and that the straddle carrier is beingmaneuvered into position to pickup a load of coils of Wire.

The straddle carrier 10 is first maneuvered into a position such thatthe ram 30 is positioned adjacent one end or" a series of coils of wireand is aligned such that the axis of the ram 31 is parallel with andabove an axis through the openings in the coils. The operator thenmanipulates the operating lever of the valve 102 to cause the load hooksto lower the coil handling attachment until the ram is positionedcoaxially with the coils. The straddle carrier 11 is then movedforwardly such that the ram 30 passes through the series of coils andprojects outwardly through the opposite end thereof.

The operating lever 112 of the valve 119 is then manipulated into thegate close position and the rotary hydraulic motor 64 will thus beoperated to close the gate member 49 over the end of the ram 30. Whenthe gate member has reached the fully closed position the sequence valve116 will automatically cause the hydraulic cylinder 82 to then beactuated to engage the locking plate 76 into position within the slot 72in the stub shaft 70 on the ram 30. The closing movement of the gatemember 40 will close the circuit through the gate switch 185 and openthe circuit through the gate switch 148. The opening of the circuitthrough the gate switch 143 opens the circuit through the red indicatorlight 174. The closing of the circuit through the gate switch 185 andthe subsequent closing of the switch 188, by movement of the lockingplate 76 into position, closes the circuit through the green indicatorlight 172 and also closes a the circuit to energize the solenoid 146 ofthe valve 144,

eliminating the series connection between the main relief valve 142 andthe secondary relief valve 150, thereby making it possible for thecylinders 104 and 1% to be actuated to cause the load hooks to raise thecoil han dling attachment 20 for transporting to the destination. Theclosing of the circuit through the green indicator light 172 indicatesto the operator that .the unit is in a safe condition for transportingthe load.

The operator then manipulates the operating lever of the control valve102 to cause the cylinders 104 and 106 to be actuated to raise the loadhooks and thus the coil handling attachment 20. The straddle carrier 10may then be driven to the unloading destination. be noted that since thegate member 40 is securely locked into position over the end of the ram30, there is provided a rigid structural support for the loaded ram andthe straddle carrier can be driven over rough surfaces or forwardly downinclined ramps Without danger of any of the coils becoming disengagedfrom the ram 30.

When the unloading destination has been reached, the operator thenmanipulates the operating lever of the control valve 102 to cause thecylinders 104 and 106 to be actuated to lower the load hooks to aposition such that the coils are supported on the ground or othersupporting surface. The operating lever 112 of the control valve is thenmanipulated to the gate open posi tion thereby rendering the sequencevalve 124 eifective to cause the cylinder 82 to be actuated to disengagethe locking plate 76 from the ram. When the cylinder 82 has completedits full stroke, the sequence valve then automatically causes the rotaryhydraulic motor 64 to be operatedto pivot the gate member/t0 to its fullopen position.

The straddle carrier 10 may then be backed away from the series of cellsthereby withdrawing the ram 31) and the carrier is then in condition topick up an additional load if desired.

While one illustrative embodiment of an improved coil handlingattachment has been shown and described herein, it is obvious thatvarious modifications may be made therein without departing from thespirit of the invention. To those skilled in the art of makingmechanisms of the character described, many additional alterations anddifferent embodiments and applications of this invention will suggestthemselves without departing from the spirit and scope thereof.Therefore, the particular disclosure herein is intended to beillustrative only, and We do not intend to be limited thereto norotherwise than by the terms of the appended claims.

What We claim as new and desire to secure by Letters Patent of theUnited States is:

1. A material handling device comprising frame means, a ram membersecured at one end to said frame means, gate means supported from saidframe means and movable between open and closed positions relative tothe other end of said ram member, elevator means for raising said framemeans, and control means operatively connected to said elevator meansproviding in said elevator means a relatively large load liftingcapacity when said gate means is in its closed position and a relativelysmall load lifting capacity when said gate means is in its openposition.

It should 2. A material handling device comprising frame means, acantilever ram member secured at one end to said frame means, gate meanssupported from said frame means and actuatable between supporting andnon-supporting positions relative to the free end of said ram member,load lifting means for raising and lowering said frame means, andinterlocking control means operatively connected to said load liftingmeans and to said gate means for providing said load lifting means witha relatively large load lifting capacity when said gate means is insupporting position and with a relatively small load lifting capacitywhen said gate means is in its nonsupporting position.

3. A portable load handling device for use with a straddle carrier orthe like having load hooks and means normally operable to elevate theload hooks, comprising a load supporting frame adapted to be engaged andelevated by the load hooks, a load engaging cantilever ram membersecured at one end to said frame, a gate member pivotally attached tosaid frame adjacent the unsup ported end of said ram member for openingand closing movement relative thereto, drive means for opening andclosing said gate member, locking means for securing said gate memberwhen closed to said ram member, sequential control means for effectingsequential operation of said drive means and said locking means duringopening and closing of said gate member, and interlocking control meansresponsive to the position of said gate member for preventing elevationof said load hooks when said load hooks support thereon more than apredetermined load and the said gate member is open and permitting elevation of said load hooks when said load hooks support thereon more thansaid predetermined load and the said gate member is closed.

4. For use with a vehicle having load lifting means, a load handlingdevice comprising frame means adapted to be engaged by the load liftingmeans, an elongated ram member having one end secured to said framemeans, a gate member secured to said frame means adjacent the normallyunsupported end of said ram member and ac tuatable into open and closedpositions relative to the urn supported end of said ram member forsupporting said normally unsupported end when in a closed position, andinterlocking control means operatively connected to the load liftingmeans and to the gate member for providing in the load lifting means afirst load lifting capacity when said gate member is open and the secondload lifting capacity which is more than the said first load liftingcapacity when said gate member is closed.

5. A load handling device comprising frame means, a cantilever rammember secured to said frame means, a gate member secured to said framemeans adjacent the unsupported end of said ram member and actuatable between open and closed positions relative to the unsup ported end of saidram member, a fluid pressure system comprising fluid drive meansoperatively associated with said gate member for actuating said gatemember between its open and closed positions, fluid actuated means forsecuring said gate member in its closed position to said ram member, amain control valve for selectively directing fluid flow through saidsystem in a first or second direction or diverting fluid flow from saidsystem, fluid sequence control means, said control means comprising afirst sequence valve connected to said main control valve for causingfluid flowing in said first direction to be directed first to said drivemeans and then to said securing means and a second sequence valveconnected to said main control valve for causing fluid flowing in saidsecond direction to be directed first to said securing means and then tosaid drive means, fluid lifting means for selectively raising andlowering said frame means, and interlocking control means for providingsaid lifting means with a large lifting capacity when said gate is inits closed position and a small lifting capacity when said gate is inits opened position.

6. A material handling device comprising frame means, a cantilever rammember secured to said frame means, a gate member secured to said framemeans adjacent the unsupported end of said ram member and actuatablebetween open and closed positions relative to the unsupported end ofsaid ram member, fluid pressure actuated means for selectively raisingand lowering said frame means, and control means operatively connectedto said fluid pressure actuated means providing therefor a relativelyhigh load lifting capacity when said gate member is in its closedposition and a relatively low load lifting capacity when said gatemember is in its open position, said control means including relativelyhigh and low pressure responsive valve means, and other valve meansresponsive to the open and closed positions of said gate member foroperatively connecting said high pressure valve means with said pressureactuated means when said gate member is in one position and said lowpressure valve means with said pressure actuated means when said gatemember is in the other position.

7. A material handling device comprising frame means, a cantilever rammember secured to said frame means, a gate member secured to said framemeans adjacent the unsupported end of said ram member and actuatablebetween open and closed positions relative to the unsupported end ofsaid ram member, fluid pressure actuated means for selectively raisingand lowering .said frame means, and control means operatively connectedto said fluid pressure actuated means providing therefor a relativelyhigh load lifting capacity when said gate member is in its closedposition and a relatively low load lifting capacity when said gatemember is in its open position, said control means including arelatively high pressure relief valve, a relatively low pressure reliefvalve, two position valve means arranged to selectively connect saidhigh and low pressure relief valves to said pressure actuated means, andswitch means operatively connected to said two position valve means andresponsive to the position of said gate member, said switch means andtwo position valve means being arranged to connect said high pressurerelief valve to said pressure actuated means when said gate member isclosed and said low pressure valve means to said pressure actuated meanswhen said gate member is open.

8. For use with a straddle carrier, the combination comprisingsupporting frame means, an elongated cantilever ram'member attached tosaid frame means, a gate member connected to said frame means adjacentthe unsupported end of said ram member and actuatable between open andclosed positions relative to the unsupported end of said ram member,fluid pressure actuated load means for elevating said frame means, afluid system including means for selectively locking and unlocking saidgate member in its closed position to said ram .member, fluid motormeans connected to said gate memher for opening and closing said gatemember, first valve means for causing pressure fluid to be directedfirst to said fluid motor means and then to said locking means forclosing of the gate member and second valve means for causing pressurefluid to be directed first to said locking means and then to said fluidmotor means for opening of the gate member, and interlocking controlmeans operatively connected to said load means and to said gate memberproviding a relatively large load lifting capacity of said load meanswhen said gate member is closed andlocked and a relatively small liftingcapacity when said gate is unlocked and open, said control meansincluding relatively high and low pressure responsive valve means, andother valve means responsive to the open and closed positions of saidgate member for operatively connecting said high pressure valve meanswith said pressure actuated load means when said gate member is in oneposition and said low pressure valve means with said pressure actuatedload means when said gate member is in the other position.

9. In combination, longitudinally extending frame means, alongitudinally extending cantilever member attached at one end to oneend of said frame means, a gate member attached to the other end of saidframe means and actuatable between opened and closed positions relativeto the unsupported end of said cantilever member, means for selectivelyraising and lowering said frame means, means for locking said gatemember in its closed position to said cantilever member for supportingthe said unsupported end of said latter member, and control meansoperatively connected to said raising and lowering means for providingsaid raising and lowering means with a first load raising capacity whensaid gate member is closed and locked and a second load raising capacityless than said first capacity when said gate mem her is open.

1,178,159 Holmes Apr. 4, 1916 2,103,984 Indge Dec. 28, 1937 2,265,800 7Connor Dec. 9, 1941 2,718,321 Westermeyer Sept. 20, 1955 2,732,083 SmithJan. 24, 1956 2,737,393 Held Mar. 6, 1956 2,764,298 Anjeskey Sept. 25,1956 2,975,922 Dodge Mar. 21, 1961

1. A MATERIAL HANDLING DEVICE COMPRISING FRAME MEANS, A RAM MEMBER SECURED AT ONE END TO SAID FRAME MEANS, GATE MEANS SUPPORTED FROM SAID FRAME MEANS AND MOVABLE BETWEEN OPEN AND CLOSED POSITIONS RELATIVE TO THE OTHER END OF SAID RAM MEMBER, ELEVATOR MEANS FOR RAISING SAID FRAME MEANS, AND CONTROL MEANS OPERATIVELY CONNECTED TO SAID ELEVATOR MEANS PROVIDING IN SAID ELEVATOR MEANS A RELATIVELY LARGE LOAD LIFTING CAPACITY WHEN SAID 